This disclosure is generally directed to a device and a method for generating vacuum. In particular, this disclosure is directed to a device, which includes a charge valve and an electronic controller, and a method for generating vacuum used to test a vacuum detection device.
It is frequently desirable to test the performance of a component prior to installing the component in its intended environment. An integrated pressure management system is an example of such a component that may be tested before being installed on a vehicle. The integrated pressure management system performs a vacuum leak diagnostic on a headspace in a fuel tank, a canister that collects volatile fuel vapors from the headspace, a purge valve, and all the associated hoses and connections.
It is desirable to test components in an environment that simulates the intended operating environment. A simulated environment that is suitable for testing the vacuum leak diagnostic of integrated pressure management systems can include an adjustable vacuum level.
Known vacuum generating methods suffer from a number of disadvantages including the inability to generate vacuum levels in the desired testing range (i.e., conventional vacuum generators are not stable below two inches of water), the inability to precisely control the vacuum level, and the inability to perform a test in an acceptable period.
It is believed that there is needed to provide a device and a method that overcome the disadvantages of conventional vacuum generators.
The present invention provides a vacuum-generating device. The vacuum-generating device includes a member that defines a passage, a first valve, a second valve, a fluid communication conduit, a transducer, and a processor. The passage extends between a first end and a second end, and includes a constriction that defines an orifice. The first valve connects the first end of the member and an ambient environment, and is electrically positionable in first and second configurations. The first configuration permits generally unrestricted fluid flow between the orifice and the ambient environment, and the second configuration substantially prevents fluid flow between the orifice and the ambient environment. The second valve has a first port and a second port. The first port is adapted for fluid communication with a pressure source at a first pressure level. The second valve is electronically adjustable. The fluid communication conduit connects the second end of the member and the second port of the second valve. The fluid communication conduit includes a fluid communication tap at a second pressure level. The transducer is in fluid communication with the fluid communication tap. The transducer senses the second pressure level and outputs a first electric signal. And the processor is in electrical communication with the second valve and with the transducer. The processor receives the first electric signal from the transducer and outputs a second electric signal to the second electric actuator. The second valve varies fluid flow through the orifice in response to the second electric signal.
The present invention also provides a method of testing a vacuum detection device. The method includes providing a pressure source at a first pressure level, connecting the vacuum detection device to a vacuum generating device, drawing with the vacuum generating device a vacuum at a second pressure level, sensing the second pressure level, processing, and varying fluid flow through the vacuum generating device. The vacuum-generating device includes a passage, a first valve, a second valve, and the fluid communication conduit. The passage includes a constriction that defines an orifice. The first valve connects the passage and an ambient environment, and is electrically positionable in first and second configurations. The first configuration permits generally unrestricted fluid flow between the orifice and the ambient environment, and the second configuration substantially prevents fluid flow between the orifice and the ambient environment. The second valve is in fluid communication with the pressure source and is electronically adjustable. The fluid communication conduit connects the passage and the second valve, and includes the fluid communication tap, which is at a second pressure level. The vacuum detection device is connected to the fluid communication tap. The sensing includes outputting a first electric signal commensurate with the second pressure level, and the processing includes outputting a second electric signal based on the first electric signal. And the varying includes adjusting the second valve in response to the second electric signal.